The transition to digital video allows video programming to be transmitted in a digital format through satellite systems, cable systems, and over the air broadcast systems. Digital compression, and in particular, the Motion Pictures Expert Group (MPEG) Standard allows for multiple digital programs to be carried in a section of spectrum which previously could only carry one analog program. Typically, the 6 MHz wide channel which carried one analog program can carry six to ten digitally encoded and compressed programs.
As part of the digital transmission process, multiple programs are statistically multiplexed such that the bit rate requirements for each program are met and when programs do not have a high bit rate requirement, other programs can use the available bandwidth. As an example, when a football game is statistically multiplexed with a talk show, the football game will be allocated sufficient bandwidth to permit accurate representation of the play on the field and the motion of the players. The talk show program will be allocated a minimum amount of bandwidth such that the people appearing on the program can be seen clearly. However, in an instance when there is motion in the talk show program as may be the case when the participants on the talk show begin to hurl chairs at one another, the multiplexing process will allocate additional bandwidth to the talk show and in the event that there is a minimum bandwidth requirement in the football game, that bandwidth will be allocated from the football game to the talk show. Clearly, when there are multiple programs, bandwidth can be allocated among all the programs such that the motion can be accurately represented in each program and the overall statistically multiplexed stream optimized.
Several problems arise in statistically multiplexed programs including the difficulty in separating programs and substituting provisional programming. As an example, at a re-transmission point such as a cable television local head end it becomes difficult to remove one program from the statistically multiplexed stream and insert another program. This difficulty arises from the fact that the bandwidth of the program is varying constantly according to the bandwidth tradeoffs achieved by the statistical multiplexing equipment at the origin point.
Another difficulty is the insertion of advertisements into the statistically multiplexed streams. Because the bandwidth of each program is varying, an original advertisement inserted into the program stream at the origin point will have a time varying bandwidth. Inserting another advertisement at the re-transmission point is not readily facilitated in existing systems and equipment because the bandwidth is varying and in some cases not easily discernible by the equipment at the re-transmission point. Because local advertisement insertion is an important part of many broadcast services and generates significant revenue, it is necessary to be able to remove the initial advertisements, which are part of the program stream and substitute new advertisements.
U.S. Pat. No. 5,715,018 entitled “Digital Advertisement Insertion system” issued on Feb. 3, 1998, provides means for digitizing, compressing and storing analog/audio video source information; and decompressing the information to regenerate an analog signal. A method based on this patent includes receiving motion video information from an analog source; digitizing, compressing and storing the received motion video information in a computer data file such that upon decompression, broadcast quality motion video information is obtained; selecting and editing at least a portion of the stored motion video information; decompressing the selected and edited portion of the stored motion video information to obtain broadcast quality motion; and regenerating an analog signal from the selected and edited portion of the stored motion video information; inserting the regenerated analog signal in place of a broadcast signal on a channel at a predetermined time; and providing synchronization of the regenerated analog signal to the broadcast signal.
An apparatus based on this patent includes means for inserting a signal representing motion video information in place of a broadcast signal on a broadcast channel at a predetermined time, and wherein the broadcast channel transmits the motion video information at a field per second rate; means for providing synchronization of the signal representing motion video information to the broadcast signal; a randomly-accessible computer-readable medium for digitally storing in a data file compressed image data for a sequence of digital still images, including an image corresponding to each field of the motion video information to be transmitted in the broadcast channel, such that upon decompression, broadcast quality motion video information is obtained; and a computer including means for editing the sequence of digital still images, means for accessing the sequence at the predetermined time, for decompressing the sequence to obtain broadcast quality motion video information and for generating the signal to be inserted into the broadcast channel from the accessed sequence.
U.S. Pat. No. 5,600,366 entitled “Methods and Apparatus for Digital Advertisement Insertion in Video Programming”, issued on Feb. 4, 1997 permits timely and correct switchovers from network programming to local advertising in ways which occur smoothly without disruption in perception to the viewer. Switchovers occur at packet or frame boundaries and are designed to occur upon detection of idle information from a network source. An apparatus based on this patent includes means for receiving externally supplied programming comprising analog video information and embedded tone cues including a pre-roll cue and a roll cue, detecting said tone cues and converting the analog video information to digital video information; means for activating digital video storage in response to one of said tone cues preparatory to initiating playback; and means for initiating playback from said storage in response to detecting an idle condition from said digital video information.
Another apparatus based on this patent includes means for receiving externally supplied programming from a plurality of sources, each source providing programming comprising analog video information and embedded tone cues, and for converting the analog video information to digital video information; storage means for storing a plurality of local programs; common means for monitoring all of said sources to detect one or more tone cues from a source and for preparing said storage means for playback of respective one or more of said local programs to be substituted for said externally supplied programming from a source sending at least one of said one or more tone cues; and means for initiating playback from said storage means of respective one or more of said local programs to be substituted for said externally supplied programming from a source in response to detecting an idle condition from said digital video information of said source.
A method based on this patent includes receiving externally supplied programming comprising analog video information and embedded tone cues including a pre-roll cue and a roll cue, detecting said tone cues and converting the analog video information to digital video information; activating video storage in response to one of said tone cues preparatory to initiating playback; and initiating playback from said recorder in response to detecting an idle condition from said digital video information.
Another method based on this patent includes receiving local digital video programming and providing it to a user; receiving externally supplied analog video programming and embedded tone cues including a return to network cue, detecting said return to network cue; converting said analog video programming to digital video information upon receipt of said return to network cue; and terminating operation of video storage in response to detection of an idle condition in said local digital video programming.
U.S. Pat. No. 5,956,088 entitled “Method and Apparatus for Modifying Encoded Digital Video for Improved Channel Utilization” issued on Sep. 21, 1999 and U.S. Pat. No. 5,862,140 entitled “Method and Apparatus for multiplexing Video Programs for Improved Channel Utilization” issued on Jan. 19, 1999 both provide a method (and apparatus) for increasing channel utilization for a data channel transmitting a multiplex of a set of one or more encoded program streams. Each program stream in said set being decodable by a corresponding decoder. Each corresponding decoder including a corresponding decoder buffer, the decoder buffers having a maximum allowable size. The method comprising selecting encoded pictures to be modified, said selecting according to a criterion, which includes preventing any underflow of any decoder buffer, modifying each said selected encoded picture to form a corresponding modified encoded picture, said modified encoded picture having less data than said selected encoded picture, and transmitting the corresponding modified encoded pictures through the channel in place of the selected encoded pictures. In one embodiment of these patents, modifying deletes each selected encoded picture. In another embodiment of the patents, where the encoded program streams include predictively encoded pictures, selecting selects predictively encoded pictures that are not anchor pictures, and modifying deletes the prediction error data from each said selected encoded picture.
In a further embodiment of these patents, one or more additional data channels are used to send augmentation information. The augmentation information can be used by specially equipped receivers to correct the impairments that would normally occur when decoding the modified signal received from the data channel. In yet another embodiment of the patent, augmentation information is sent using the same data channel that is used to transmit the modified pictures. In this case, the information that is removed by modifying is transmitted before it is needed for decoding and at a time when the data channel is not fully utilized. Certain receivers equipped with sufficient storage can receive and store the augmentation information until it is needed. Alternatively, if the additional storage is used to insert additional delay between the time that data is received and the time that data is decoded, then the augmentation information can be sent after it would be needed by a conventional receiver.
A system of these patents comprise primary and overflow demodulators configured to demodulate data from the primary and overflow channels, respectively; a first demultiplexer, coupled to the primary demodulator, configured to extract a primary packet stream from an output of the primary demodulator; a second demultiplexer, coupled to the overflow demodulator, configured to extract an overflow packet stream from an output of the overflow demodulator; a buffer coupled to the second demultiplexer; a time stamp comparator, coupled to the first demultiplexer and the buffer, configured to compare a time stamp associated with a next packet from the primary packet stream with a time stamp associated with a next packet from the overflow packet stream; and a packet multiplexer, coupled to the first demultiplexer, the buffer and the time stamp comparator, configured to select one of the next packets from the primary packet stream and the overflow packet stream in response to a comparison made by the time stamp comparator.
U.S. Pat. No. 5,029,014 entitled “Ad Insertion System and Method for Broadcasting Spot Messages Out of Recorded Sequence”, issued on Jul. 2, 1991, provides an advertisement insertion system and method transmit spot messages during intervals in a broadcast transmission and provide immediate access to stored spot messages, in any sequential order, with a single video source. Custom spot messages can be created by superimposing graphics over selected video signals and simultaneously transmitting those signals with appropriate audio signals.
A system of this patent comprises a first playing means for playing spot messages stored in a recorded sequence on a video source, and control means for switching a broadcast system from program signals of a scheduled broadcast, selecting and causing said first playing means to play into said broadcast system in immediate succession a plurality of spot messages out of said recorded sequence without intervening material from another playing means, and switching said broadcast system back to program signals of a scheduled broadcast.
A method of this patent comprises selecting video, audio and/or graphic signals to form custom spot messages; accessing the selected video signals on a laser disk; accessing selected audio signals which are to be simultaneously broadcast with said accessed video signals; and switching from broadcast transmission to spot message transmission to co-broadcast said accessed video and audio signals as said spot messages with an audio component according to a programmed time schedule and out of a pre-recorded sequence of spot messages on said laser disk.
U.S. Pat. No. 5,966,120, entitled “Method and Apparatus for Combining and Distributing Data with Pre-formatted Real-time Video”, issued on Oct. 12, 1999, relates to providing constant bit rate distribution of variable bit rate-encoded video programs, along with Auxiliary Data of a general character, to one or more receivers. At a particular receiver, a customized augmented video program is created by inserting selected portions of the Auxiliary Data into a selected encoded video program. The encoded video portion of the augmented video program can be transmitted, decoded and displayed in real time, while the Auxiliary Data need not be transmitted in real time but can be stored locally at the receiver for real-time presentation at a later time. Real time presentation might include insertion into the video program while non real-time presentation might include insertion into non-video applications separate from the video program.
A method of this patent comprises the steps of receiving the primary data stream; detecting fill data in the primary data stream; inserting an auxiliary data stream in place of the fill data; and adding location data for the programs and for the auxiliary data; to form a modified data stream for distribution to a plurality of receivers configured for individually extracting selected portions of the modified data stream in accordance with the location data.
Another method of this patent comprises the steps of statistically multiplexing a plurality of encoded video programs; monitoring the statistically multiplexed encoded video programs for the occurrence of a fill packet; maintaining a buffer of auxiliary data segments; replacing the fill packet with at least one segment of the auxiliary data stream from the buffer if the segment is smaller than the size of the fill packet; adding location data for the encoded video programs and for the auxiliary data; to form a modified data stream for distribution to a plurality of receivers configured for individually extracting selected portions of the modified data stream in accordance with the location data.
A system of this patent comprises a program multiplexer for statistically multiplexing a plurality of encoded video programs to the modified data stream; a data insertion controller coupled to receive a multiplexed program stream from the program multiplexer and for inserting auxiliary data therein to yield a modified data stream; and a program map insertion controller coupled to receive the modified data stream for adding location data for the encoded video programs and for the auxiliary data to the modified data stream. Another system comprises a multiplexer for statistically multiplexing a plurality of encoded video programs; a first controller for adding auxiliary data to the output of the multiplexer; a second controller for adding location data for the encoded video programs and for the auxiliary data to the output of the first controller, thereby forming a modified data stream; a distribution channel for distributing the modified data stream to at least one receiver; a processor for determining location data from the distributed modified data stream; a first demultiplexer for selecting an encoded video program from the modified data stream in accordance with a first predetermined characteristic of the processor and the location data; a second demultiplexer for selecting local auxiliary data from the modified data stream in accordance with a second predetermined characteristic of the processor and the location data; a storage device for storing the local auxiliary data from the second demultiplexer; and an augmentation unit for associating the encoded video program and the stored local auxiliary data to form a receiver-specific augmented video program for decoding and display.